Aggregator operators

The Aggregator processor supports several standard operators for computing aggregate values over events in each partition, including sum, avg, min, max, count, and delta.

Consider the following example of a single partition where CustomerID is CUST1 and the events are ordered by timestamp:

CustomerID	Timestamp	API_Calls
CUST1	2025-10-01 10:01	5
CUST1	2025-10-01 10:15	3
CUST1	2025-10-01 10:45	7

The following table describes the operators and their output based on the example data:

Operator	Description	Example output (for CUST1)	Processing logic
sum	Adds all values in the partition	15	5 + 3 + 7 = 15
avg	Computes the average (mean)	5	(5 + 3 + 7) ÷ 3 = 5
min	Finds the lowest value	3	Minimum API call count is 3
max	Finds the highest value	7	Maximum API call count is 7
count	Counts the number of records	3	Three records for CUST1
delta	Computes the difference between consecutive values	1st row = – , 2nd = 3-5 = -2, 3rd = 7-3 =4	Shows change in API_Calls compared to the previous record